Can anyone explain this Data usage?

What's happening is my iPhone 4 is suddenly using 3G data at random dates. Usually in the evening 7pm or 10pm (Arizona Time) and even once at 1AM. The part that really bothers me is these have all been times when I'm home and on my wireless network. Why would my phone use 3G when I'm automatically on wi-fi?

The amounts vary from 7KB to a couple times over 100,000KB! The billing detail describes it as "Internet/MEdia Net" sent from my phone.

This is the first month that I noticed the data usage because this is the first time it's reached such high amounts that AT&T sent us a warning. I have a 200mb monthly plan. I'm a little over a week in and already over 114mb!

Related note: After the notice from AT&T I checked my notification and iCloud settings and somehow they had been changed and a lot of stuff was turned on that I turned off. No one's had access to my phone and I know I didn't make the changes. After I set everything back, the usage has dropped significantly. But still... why the 3G at all??

16GB iPhone 5, 64GB Wi-Fi only iPad 1st Gen.

Reminder: Please include your Mac's specs. This will make it much easier for the other members to assist you.

Well, after some searching on AT&T's forums and their customer support site I found that the name is what they use for all internet access. Basically any data use by an app or web browsing. But there's no way I'm using that much a day and especially at those hours. That's what bugs me and worries me.

16GB iPhone 5, 64GB Wi-Fi only iPad 1st Gen.

Reminder: Please include your Mac's specs. This will make it much easier for the other members to assist you.

I remember seeing something about this when I first got the iPhone about a year ago. It's annoying me that I can't find the reference now. Seems like part of the issue was making use of push for email etc. seems like the wireless network was not being used as much as possible.